Strangeness enhancement in sulphur—Nucleus collisions at 200 A GeV/c

Abstract

The NA35 experiment used several independent methods to determine the strange particle production in p+S and S+A collisions. The different techniques show consistent results. Strangeness conservation in full phase space is used as an additional check of the consistency of the data. On the base of the analysis in full phase space it could be shown that strangeness conservation is fullfilled. The NA35 K$^0_S$ in S+S and S+Ag are consistent with the NA44 results for K$^+$ and K$^-$. The results of the NA36 collaboration for S+Pb collisions were extrapolated to full phase space. The comparison with the NA35 results shows more than two times lower yields. The ratio of $\Lambda$ to $\overline{\Lambda}$ at midrapidity of NA36 is inconsistent with the high baryon density determind by NA35. The strange particle production is compared to the abundance of non strange particles, especially negatively charged pions which are measured in full phase space in the same experiment. A clear enhanced strange hadron production relative to $\pi^-$ is observed in S+Ag collisions compared to p+S reactions at the same energy. The K$^0_S$ multiplicity in full phase space per negative hadron (h$^-$) in S+S, S+Ag and Pb+Pb is enhanced by about a factor 1.6 compared to N+N and p+S collisions. The NA36 result for the K$^0_S$ multiplicity per h$^-$ in S+Pb is below the N+N value.